What is post-infectious irritable bowel syndrome (IBS)?

Post-infectious irritable bowel syndrome (PI-IBS)

Post-infectious irritable bowel syndrome (PI-IBS) is a form of IBS that is caused by food poisoning or a "stomach bug". (1)

The exact event of food-borne gastric infection may not be remembered as symptoms can develop and progress a long time after the initial infection. For some this may be weeks, for other years.

One in nine individuals who experience food poisoning can go on to develop post-infectious IBS, according to a review of over 45 studies by the Mayo clinic. (2)

Abdominal pain and frequent diarrhea (IBS-D) are the predominant symptoms, but occasionally the mixed type of IBS (IBS-M) can be present with alternating diarrhea and constipation. (3)

Cramping, bloating, excess gas, bowel urgency, and unpredictability can also occur. (3)

It must be noted that those who are constipation predominant (IBS-D) are unlikely to have post-infectious IBS as their root cause, according gastroenterologist Dr Mark Pimentel, the creator of the IBS-Smart test. (4)

What is the IBS-Smart test?

Post-infectious IBS is now thought to be detected by measuring the presence of certain antibodies in blood samples. These are known as anti-vinculin and anti-CdtB antibodies. (4, 5, 6)

Causes of PI-IBS

Common gastro bugs that cause food poisoning include bacteria such as Shigella, Campylobacter, Salmonella, and E. Coli. (7)

The bacteria release a toxin known as cytolethal distending toxin-B (CdtB) when they infect the body. (8)

When a toxin, such as CdtB, enters the body, it triggers an immune response through the creation of an antibody, anti -CdtB.

Vinculin, a naturally occurring protein required for healthy gut function, is unfortunately similar in structure to CdtB. This similarity can trick the body into attacking vinculin by producing anti-vinculin antibodies, which can damage the gut and lead to a worsening of symptoms. Production of anti-vinculin antibodies could be considered an autoimmune disease, as the body is effectively attacking itself.

More specifically, vinculin is a protein of nerve cells that line the gut, so the anti-vin

culin antibodies can destroy these nerve cells leading to alterations in gut motility. The infection may be gone, but the damage has been done and gut healing is required.

Because gut motility is impacted, a bacterial overgrowth (SIBO) can also occur. If SIBO keeps recurring, the nerve damage from anti-vinculin antibody attack can be an underlying reason.

Viruses, like Norovirus, and even parasites, like giardia, may also be a cause of elevated anti-vinculin levels, causing IBS, according to Dr Pimentel.

Elevated levels of anti-CdtB and/or anti-vinculin are thought to indicate post-infectious IBS with high certainty. However, it does not distinguish whether the cause was bacterial, viral or even parasitic in origin. (9)

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What is irritable bowel syndrome (IBS) and what causes it?

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